We want to find the etiology of vitiligo, i.e., to determine how epidermal melanocytes are destroyed to leave white patches of skin; to perfect an effective treatment for patients with vitiligo by using transplants of autologous pigment cells; and to test the possibility of harnessing the etiological factors responsible for the destruction of pigment cells in vitiligo to slow or halt the proliferation of malignant pigment cells in patients with melanomas. In addition, having cloned the cDNAs for human and murine tyrosinase, we are in position to attempt the correction of murine and human albinism. Our objectives for the 1989-1994 period of support include: 1. To perfect an effective treatment for vitiligo by transplanting autologous pigment cells into depigmented epidermis of human beings with vitiligo. 2. To understand the mechanism of pigment cell loss in vitiligo and in the Ler-vit/vit mouse. 3. To identify and correct the gene defect in human and murine albino melanocytes. 4. To determine the incidence of melanoma in Ler-vit/vit mice. 5. To transform Ler-vit/vit melanocytes experimentally. 6. To suppress the proliferation of malignant melanocytes in a select group of patients with melanomas.